Manufacture of artificial marble and stone.



an atmos heric A UNITED srA i Es- PATENT OFFIGE- THOMAS ArHIEsoN'rHoi i, OF CHESHUNT ENGLAND.

MANUFACTURE *OF RTIFIQ'IA; MAFiBLE AND s-rous.

To all whomg-it may concern: a

Be it known that I, Tnomss MATHIESON THOM, lithographer, a subject of the King of Great Britain, and a resident of 'Woodlands, Cheshunt, in the county of Hertfordshire, England, have invented new and useful Imfiovements in the Manufacture of Artificial arble and Stone, of which the following is a s ecification.

he prescntinvention has reference to the manufacture of artificial marble and stone,

- which consists in submitting blocks or slabs of lime to the action of carbonicacid gas in a closed vessel.

Hitherto the carbonic-acid gas has been forced into the vessel containing the slabs,

and the pressure has been maintained and from time to time increased as may be necessary durin the pro ess of the carbona-' tion. Accor 'n to t e present invention the carbonic-sci gas is not used under pressure.

On the contrary, the vessel containing the slabs to be carbonated is exhausted by means of a pump, and a vacuum is produced as complete ,as possible. When a vacuum amounting to twenty-seven inches or thereabout has been obtained, the car-, bonic-acid gas (CO is admitted to the vessel until the vacuum-gage registers only about five inches (or approximately five-sixths of ressure) instead of twentyhardening of the slabs proseven. s the gresses the gas is taken up by the stones, and

' Specification of: Letters Patent. Application flied Apr l 27, I906. Barlal'No 314.061.

' Patented July a, 19cc.

the vacuum again begins to increase and the ressure to decrease. More gas' shouldthen 5 e admitted, so as to maintain the'gage as nearly aspossible at five inches vacuum, (representing approximately five-sixths of an atmospheric ressure,) and the admission of the gas shou d be repeated as often as nec- 4o essary. When the vacuum in the vessel ceases to show an increase, it will be evident that the action of the as on the stones has become suspended, an the latter may then be-removed.

What I claim, and desire to secure by Letters Patent of the United States, is

The process of manufacturing artificial marble and stone which consists in subjecting the slabs while in a vacuum to the action 50 THOMAS MATHIESON mom.

Witnesses:

LOVELL NEWTON REnnrE, ALFRED S. BISHOP. 

